Improvement in processes of bleaching jute for paper-pulp



To all whom it may concern:

process, I first assort, clean, and cut up the jute or jute-butts in the usual way.

in an ordinary rag-engine in the usualway,

UNITED STATES EDWARD costar, CINCINNATI, OHIO.

IMPROVEMENT l N PROCESSES 0F BLEACHING JUTE FOR PAPER-PULP.

. Specification forming part of Letters Patent No.

165,307, dated July 6, 1875; application filed February 19, 1874.

Be it known that I, EDWARD (Journey, of Cincinnati, in the county of Hamilton and State of Ohio, have invented a new Improvementin the Manufacture of Paper-Pulp and I do hereby declare the following to be a full, clear, and exact description of the same.

In my invention or process there is no very radical change or important departure from certain chief steps of previous ones of the class in which the vegetable material is subjected to the action of caustic alkali, boiled under pressure. My discovery, therefore, relates to the quantitative proportions of jute and the alkaline solution, the degree of pressure to which they are subjected, the length of time the boiling is continued, and the subsequent thorough washing in warm water.

As a preliminary step to carrying out my I then put the same into a close vessel, either stationary or revolving. To every one hundred pounds of jute is added sixty gallons of caustic alkali of a strength of 7 Baum at a temperature of 130 Fahrenheit. Then boil for about ten hours under a standard pressure of eighty pounds. The boiling completed, the spent liquor is drawn off, and the stock thoroughly washed with hot water, which keeps the thick vegetable matter in solution, and carries off the black and non-fibrous substances.

Preparatory to being bleached it is washed after which I prefer to run it through a wetmachine, which extracts from it a large amount of water, and leaves itin a better condition to absorb the bleaching-liquor.

' When jute-bagging, burlaps, or gunny-bagoughly caustic except by evaporation.

prime importance: First, boiling in alkali as strong as canbe made caustic. I would use alkali of a strength of from 9 to 10 Baum, if it were practicable to make pure caustic at that strength. Alkali of any greater strength than 7 or 8 Baum cannot be made thor- Second, a combination of a caustic liquor of "a high strength and a medium pressure.

. The advantages gained by this process are as follows: First, the disintegration of the stock is effected by the single process above described. Second, thisdisintegration being thorough, the cellulose is left of a light brown color, and in its natural state short, with uneven ends, whioh is the best condition to be easily separated from the pulp, leaving pure.

cellulose. Fourth, owing to the absence of all foreign matters, paper made from pure cellulose dries out regularly when wet down for printing. This gives-to the sheet an even surface, which enables it to pass smoothly through the press, and receive a clear and distinct impression. It is also opaque, and, when printed upon, does not permit the ink to show through from one side to the other. Moreover, pure cellulose is easily bleached, only a comparatively small amount of chemicals being required, and therefore the paper made from it is'not only of the highest grade of color, but also stronger than when the pulp is subjected to a more intense chemical action.

The cellulose obtained by this process may not be chemically pure, but practically its purity is sufficient to produce all the results claimed for clear cellulose.

It has been the practice to work jute into low grades of white paper, and in small quantities. VYhen treated by this process, it can be made into the finest grades of paper, either when used alone or mixed with other stock.

I do not claim to be the first to use jute in the manufacture of white paper, so called. It has been experimented upon by many persons and in many ways, such as boiling in lime, boiling in soda-ash, giving it an acid bath, dad; but by none of the above-processes,

however, has cellulose of the desired quality vessel, of the degree of pressure and in causbeen produced. tic alkali of the strength and quantity indi- Having thus described my invention, what cated, and subsequently washing the same in I claim as new, and desire to secure by Letwarm Water, as described.

ters Patent, is EDWARD CONLEY.

The process of producing white pulp for pa- Witnesses:

per, from jute, said process consisting in boil- LISLE STOKES,

ing the specified quantity of stock in a close J AMES QUINN. 

